William e



(No Model.)

R GOATS & W. H; VIBBARD.

JACK SCREW.

No. 251,698. Y Patented Je. 3,1882.`

WITNESSES 1N VENTOBS. M MAM N4 PETER; nmmmhegnplm nnnnnnnnnnnn n. c

UNITED `STATES PATENT OFFICE.

WILLIAM R. COATS AND WILLIAM H. VIBBAltl), OF KALAMAZOO, MICH.

JACK-SCREW.`

SPECIFICATION forming part of Letters Patent No. 251,698, dated Application iled October '7, 1881.

To all whom it may concern:

Be it known that we, WM. R. COATS and WM: H. VIBBARD, citizens'of the UnitedStates, residing at Kalamazoo, in the county of Kalamazoo and State of Michigan, have invented certain new and useful Improvementsin Jack- Screws, of which the following is a specification, reference being had therein to the accompanying drawings.

Our invention relates to jack-screws; and it consists in the peculiar construction and arrangement of the parts, as hereinafter more fully described, and then pointed out inthe claims. -4

Heretofore jack screws have usually been made with stocks of cast-iron and without any means of adjusting the length of the stock,the only adjustment of which such jacks were capable being through the movement of the screw. This construction necessitated a heavy stock and allowed of but comparatively little variation in the length ofthe jack, whereas by our construction not onlyis the jack made very light, but the length ofthe stock can be readily varied.

In the drawings, Figure 1 is a side view of one of our jacks. Fig. 2 is a vertical longitudinal section of the same. excavation with the sides supported by our 3o jacks, and Figs. 4 and 5 are details of the head and foot pieces employed when the jacks are used in excavations, Snc.

A represents the base or foot piece, which may either be made' of the shape shown in Figs.

1 and 2 or of that shown in Fig. 5, as desired.

This base I usually make of cast-iron, and it may be of such size as will readily slip inside ofthe tube B, formingthe lower section of the stock; or` it may be firmly fastened to the interior of the tube by shrinking said tubes on, or by other convenient means of fastening. The upper end of this tube is provided with a screw-thread,by means of which and the union C the top section, D, of thestock is secured in place. This top section has in its upper end a nut-piece, E, which is rst firmly secured therein by weldin g or otherwise,.and then bored and tapped to receive the` screw F, which has its upper end, a, formed square or hexagonal to fit an open wrench, by means of which the Fig. 3 shows an January 3,` 1882.

(No model.) r

screw is turned. Above this portion is the head-piece or cap G, tted so4 that the screw may readily turn in it,and shaped either as shown in Figs. l-` and 2 or as shown in Fig. '4, according to the use to which the jack is to be applied.

By this construction a'jackis provided which 4may be readily usetl'in Ip sjitions where the ordinary jack isnot readi y applicable., owing to its weight and shape-such, foninstance, as that shown in Fig. 3, Where the jacks may be used as steps for the workmen in descending into excavations; or they may he used for support'- ing scaffolding on which to throw earth taken out of the excavation during the progress of the work, or for receiving materials to be put into such excavations.

The length of the stock may be varied in different ways, viz: by having a series of bases with different lengths of tubes firmly attached to them, so that by changing the lowrer section 4the jack may be extended to any/ desirable length 5 `or by havingthe base loosjelytitted to the pipe it can either be placed `in the bottom of the upper section, as shown by dotted lines in Fig. 2, or inserted in a removable extensionpiece, forming with the base the lower section ofthe stock, as shown in full lines in the same figure. The base may either be made solid or cast hollow to make it lighter andto admit of the screw passing into it when the base is inserted in the lower end of the upper section of the stock. By the use of either of these methods the stock can be extended to any desired length, and the usefulness of the instrument thus greatly extended, as there is no limit within reason to which such a jack may not be extended, whereas in the old plan the extension of the jack is limited by the screw, and recourse is had to blocking up, which is very troublesome even when the jackl is set verti,

cally, and particularlyv so when it is actin g horizontally, often resulting in seriousy accidents.

The peculiar form of base and cap shown in Figs. 4 and 5 will be found especially useful 95 where the jack is to be used against inclined surfaces, as whenused to support timbers in IOO `of an extensible stock, whereby the length of `the screw, substantially as specied.

i 2 25L69S 4. Ajnck provided with an inclined base and cap, substantially as described, andfor the purpose set forth.

In testimony whereof` We affix onr signatures in presence of two Witnesses.

the jack can be altered independently of the screw, substantially as described.

2. Thecombination,witl1 the screw ofajack, of a stock made in two or more sections7 Where by its length may be varied independently of WILLIAM R. COATS. 3. The combination, with the screw ofe jack, WM. EL VIBBARD. of a stock provided with a removable base, whereby the stock may be lengthened independently of the screw, substantially as described.

Witnesses LYnAN M. GATES, GUSTAVUS M. GATES. 

